Gear processing apparatus and method

ABSTRACT

The presented disclosure provides a gear processing apparatus, including a base, a driving unit, a bearing unit, a grinding assembly and a control unit. The driving unit, the bearing unit and the grinding assembly are arranged on the base. The bearing unit is used to carry the gear and can be activated by the driving unit to perform plural first corresponding axial movements relative to the bearing unit. The grinding assembly includes a grinding member. The grinding assembly can be activated by the driving unit to perform plural second corresponding axial movements relative to the bearing unit to contact the tooth surface of the gear by the grinding member. The control unit is used to control the driving module to apply additional movement to at least one of the plural first corresponding axial directions or/and at least one of the plural second corresponding axial directions during the grinding process to change the grinding directions of the tooth surface of the gear generated by the grinding member.

FIELD OF THE INVENTION

The present disclosure relates to a gear processing technology and, moreparticularly, to a gear processing device and method that can change thegrinding texture and roughness of the tooth surface of the gear.

BACKGROUND OF THE INVENTION

Gears are common transmission components, and the gears can be made ofdifferent materials according to different usage requirements. Forexample, when the gears are used in vehicle components or high-precisionmeasuring equipment, these gears are mostly made of hard metals oralloys in order to maintain stability and durability of operation. Forthe tooth surface of this kind of gears, grinding wheels are usuallyused for grinding to shape the tooth surface of the gear.

However, during the process of the grinding wheel processing, much finegrinding texture that cannot be seen by the naked eye are formed on thetooth surface of the gear. Since the grinding wheel always regularlygrinds the tooth surface in a single direction, the grinding texture iscorrespondingly roughly along the tooth length direction and parallel toeach other. The grind texture makes the gear easy to generate noise witha specific frequency during transmission, and is not conducive to theformation of lubricating oil film in the meshing area, which will affectthe operation efficiency and quality of the gear. Therefore, how toreduce the possibility of noise generation by improving the adverseeffects caused by the fine grinding texture formed on the tooth surfaceof the gear is indeed a topic worthy of research.

SUMMARY OF THE INVENTION

The present disclosure provides a gear processing device that can changethe grinding texture and roughness of the tooth surface of the gear.

To achieve the above-mentioned object, the gear processing device of thepresent disclosure comprises a base, a driving unit, a bearing unit, agrinding assembly, and a control unit. The driving unit, the bearingunit and the grinding assembly are arranged on the base. The bearingunit is used for bearing the gear, and the bearing unit is driven by thedriving unit to perform a motion with a plurality of first correspondingaxial directions relative to the base. The grinding assembly includes agrinding element, and the grinding assembly is driven by the drivingunit to perform a motion with a plurality of second corresponding axialdirections relative to the bearing unit, so that the grinding elementcontacts the tooth surface of the gear. The control unit is electricallyconnected to the driving unit, wherein the control unit is used tocontrol the driving unit to apply an additional motion for at least oneof the plurality of first corresponding axial directions, or/and atleast one of the plurality of second corresponding axial directionsduring a grinding process to change direction of the grinding textureproduced by the grinding element on the tooth surface of the gear.

In one of the embodiments of the present disclosure, the additionalmotion is a one-time motion or a continuous motion.

In one of the embodiments of the present disclosure, an additionalinstallation angle of the gear is adjusted by the one-time motion, sothat a center of a contact area of the grinding element and the toothsurface of the gear is not on a plane formed by an axis of the grindingelement, and a rotation axis applied the one-time motion.

In one of the embodiments of the present disclosure, the continuousmotion is a wave motion.

In one of the embodiments of the present disclosure, the wave motion isselected from at least one or a combination of the following groups: asine wave motion, a square wave motion, a triangle wave motion, or asawtooth wave motion.

In one of the embodiments of the present disclosure, the control unitcontrols the driving unit to apply the different wave motions to atleast two of the plurality of second corresponding axial directionsduring the grinding process.

In one of the embodiments of the present disclosure, the control unitcontrols the driving unit to apply the same wave motions with differentamplitudes or frequencies to at least two of the plurality of secondcorresponding axial directions during the grinding process.

In one of the embodiments of the present disclosure, the grindingelement is a grinding wheel.

In one of the embodiments of the present disclosure, the plurality offirst corresponding axial directions or the plurality of secondcorresponding axial directions are at least two selected from thefollowing groups: three moving axes and three rotating axescorresponding to six degrees of freedom.

The present disclosure further provides a gear processing method forperforming a surface processing on a tooth surface of a gear. The gearprocessing method comprises: providing a gear processing device, whereinthe gear processing device includes a driving unit, a bearing unit thatbears the gear, and a grinding assembly includes a grinding element; andapplying the driving unit to drive the bearing unit to perform a motionof a plurality of first corresponding axial directions relative to thebase or/and to drive the grinding assembly to perform a motion of aplurality of second corresponding axial directions relative to thebearing unit, so as to make the grinding element to contact the toothsurface of the gear. Wherein the driving unit applies an additionalmotion to at least one of the plurality of first corresponding axialdirections or/and at least one of the plurality of second correspondingaxial directions during a grinding process, so as to change thedirection of the grinding texture produced by the grinding element onthe tooth surface of the gear.

Accordingly, the gear processing device of the present disclosure canchange the complex grinding texture formed on the tooth surface of thegear to produce interlaced and non-parallel texture, and control thesurface roughness to avoid excitation of noises with specificfrequencies when the gear meshes and achieve the effect of noisereduction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of the gear processing device of the presentdisclosure;

FIG. 2 is a schematic diagram of the structure of the gear processingdevice of the present disclosure;

FIG. 3 is a schematic diagram of the additional motion performed by thegear processing device of the present disclosure on the rotating axiscorresponding to the bearing unit;

FIG. 4 is a schematic diagram of the change of the contact area betweenthe grinding element and the tooth surface of the gear before and afterthe additional motion shown in FIG. 3 is performed;

FIG. 5 is a schematic diagram of a comparison of the grinding results ofthe tooth surface of the gear of the control group A1 and theexperimental group B1 of the gear processing device of the presentdisclosure;

FIG. 6 is a schematic diagram of the additional motion performed by thegrinding unit of the gear processing device of the present disclosure;

FIG. 7 is a schematic diagram of a comparison of the grinding results ofthe tooth surface of the gear of the control group A2 and theexperimental groups B2˜E2 of the gear processing device of the presentdisclosure; and

FIG. 8 is a flow chart of the gear processing method of the presentdisclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to make the description of the present disclosure more detailedand complete, please refer to the attached drawings and the variousembodiments described below. The elements in the drawings are not drawnto scale and are provided only to illustrate the present disclosure. Thefollowing practical details are described in order to provide acomprehensive understanding of this disclosure. However, those ofordinary skill in the relevant fields should understand that thisdisclosure can be implemented without one or more practical details.Therefore, these details should not be used to limit this disclosure.Since various aspects and embodiments are only illustrative andnon-limiting, after reading this specification, those with ordinaryknowledge may have other aspects and embodiments without departing fromthe scope of the present disclosure. According to the following detaileddescription and patent application scope, the features and advantages ofthese embodiments will be more prominent.

In present disclosure, “a” or “an” is used to describe the units,elements, and components described herein. This is done for convenienceof description only and providing a general meaning to the scope of thepresent disclosure. Therefore, unless clearly stated otherwise, thedescription should be understood to include one, at least one, and thesingular can also include plural.

In this specification, the terms “first” or “second” and other similarordinal numbers are mainly used to distinguish or refer to the same orsimilar elements or structures, and do not necessarily imply that theseelements or structures are in space or chronological order. It should beunderstood that in certain situations or configurations, ordinal numberscan be used interchangeably without affecting the implementation of thiscreation.

In this disclosure, the terms “including”, “having”, “containing” or anyother similar terms are intended to encompass non-exclusive inclusive.For example, a component, structure, article, or device that contains aplurality element is not limited to such elements as listed herein butmay include those not specifically listed but which are typicallyinherent to the component, structure, article, or device. In addition,the term “or” means an inclusive “or” rather than an exclusive “or”unless clearly stated to the contrary.

The gear processing device of the present disclosure is configured toperform surface grinding processing on the tooth surface of the gear toreduce the surface roughness of the tooth surface of the gear. Pleaserefer to FIG. 1 and FIG. 2 collectively, in which FIG. 1 is a blockdiagram of the gear processing device of the present disclosure, andFIG. 2 is a schematic diagram of the structure of the gear processingdevice of the present disclosure. As shown in FIGS. 1 and 2, the gearprocessing device 1 of the present disclosure includes a base 10, adriving unit 60, a bearing unit 20, a grinding assembly 30 and a controlunit 40. The base 10 is the basic structure of the gear processingdevice 1 of the present disclosure, and is provided for the installationof various functional units or components.

The driving unit 60 is arranged on the base 10. The driving unit 60 isconnected to the bearing unit 20 and the grinding assembly 30, and thedriving unit 60 is used to drive the bearing unit 20 or/and the grindingassembly 30 to perform multiple axial movements, so as to facilitate thegear processing by the grinding assembly 30. The driving unit 60 may bea motor, an electric motor, or other devices capable of driving parts tomove or/and rotate.

The bearing unit 20 is arranged on the base 10. The bearing unit 20 isused to carry the gear to be processed. The bearing unit 20 includes abearing portion 22. The driving unit 60 can drive the bearing portion 22to perform a motion with a plurality of first corresponding axialdirections relative to the base 10 to cooperate with the grindingassembly 30 to process the gear. The bearing portion 22 is used to placeand fix the gear to be processed. In an embodiment of the presentdisclosure, the driving unit 60 can drive the bearing portion 22 toperform a single or multiple axial directional motion, for example,perform linear motions along the X axis and Y axis in FIG. 2 or rotatealong the A axis to change relatively the processing position of thegear. The driving unit 60 can also drive the bearing portion 22 toperform a linear motion along the Z axis. The driving unit 60 canfurther drive the bearing portion 22 to perform a rotational motionalong a rotation axis C to synchronously drive the gear to rotate. Thatis to say, in this embodiment, the aforementioned plurality of firstcorresponding axial directions are selected from at least two or acombination of the following groups: three moving axes and threerotating axes corresponding to six degrees of freedom, but the presentdisclosure is not limited thereto.

The grinding assembly 30 is arranged on the base 10. The grindingassembly 30 is used to perform grinding operations on the gear to beprocessed. The driving unit 60 can drive the grinding assembly 30 toperform a motion of a plurality of second corresponding axial directionsrelative to the bearing unit 20 to grind the gear. In the presentdisclosure, the grinding assembly 30 includes a sanding unit 31 and agrinding unit 32, wherein the sanding unit 31 includes a sanding element311, and the grinding unit 32 includes a grinding element 321. Thesanding unit 31 is used to perform sand dressing operations on thegrinding element 321 of the grinding unit 32. The grinding unit 32 usesthe grinding element 321 to contact the tooth surface of the gear togrind the gear to be processed. That is to say, in this embodiment, theaforementioned plurality of second corresponding axial directions areselected from at least two or a combination of the following groups:three moving axes and three rotating axes corresponding to six degreesof freedom, but the present disclosure is not limited to this.

For example, the driving unit 60 can drive the sanding unit 31 toperform a single or multiple axial motion, such as linear motions alongthe X1 axis and Y1 axis in FIG. 2 or rotate along the A1 axis to changerelatively the processing position of the grinding element 321. Thedriving unit 60 can also drive the sanding element 311 to perform arotational motion along a rotation axis B1 to synchronously drive thesanding element 311 to rotate. The driving unit 60 can drive thegrinding element 321 to perform a rotational motion along a rotationaxis B to synchronously drive the grinding element 321 to rotate. Asshown in FIG. 2, the motion equations of each axis in the gearprocessing device of the present disclosure are as follows:

$\quad\left\{ \begin{matrix}{\psi_{A} = \gamma_{wg}} \\{{F_{X\; 1}\left( \psi_{w} \right)} = {r_{A} + r_{w}}} \\{{F_{r\; 1}\left( \psi_{w} \right)} = {{\pm p_{w}}\frac{\psi_{w}}{2\pi}}} \\{{\psi_{A\; 1}\left( \psi_{w} \right)} = \gamma_{dw}} \\{{F_{X}\left( F_{Z} \right)} = {r_{w} + r_{g} + {xm}_{n}}} \\{{F_{X}\left( F_{Z} \right)} = {\frac{b_{w}}{b_{g}}F_{Z}}} \\{{\psi_{C}\left( {\psi_{B}.F_{Z}} \right)} = {{{\pm \psi_{B}}\frac{T_{w}}{T_{g}}\frac{b_{w}}{b_{g}}\frac{F_{Z}}{p_{w}}} + \frac{\tan\;\beta_{g}F_{Z}}{r_{g}}}}\end{matrix} \right.$

Wherein ψ represents the angle of rotation of the rotating axis, Frepresents the amount of movement of the sliding axis, and the subscriptrepresents the code of the corresponding axis in FIG. 2. r_(dg) presentsthe theoretical axis angle of the sanding element 311 and the grindingelement 321, r_(wg) represents the theoretical axis angle of thegrinding element 321 and the gear, and r_(d), r_(w) and r_(g) are thepitch radius of the sanding element 311, the grinding element 321 andthe gear, respectively. p_(w) is the wheel guide, x is the shiftedcoefficient, inn is the normal modulus, b_(w) is the length of thegrinding element 321, b_(g) is the tooth width of the gear, and T_(w)and T_(g) is the number of teeth of the grinding element 321 and thegear, respectively, β_(g) is the pitch helix angle of the gear.

In an embodiment of the present disclosure, the grinding element 321 maybe a grinding wheel. The following description takes a worm grindingwheel as an example, but the present disclosure is not limited to this.The axis angle of the worm grinding wheel and the gear is the additionof the wheel guide angle and the gear helix angle. The sign depends onthe respective direction of rotation. During the grinding process, thegrinding structure of the worm grinding wheel and the tooth surface ofthe gear mesh with each other to facilitate execution grindingoperations. However, in response to different needs, the axis angle ofthe worm grinding wheel and the gear can also be changed.

The control unit 40 is electrically connected to the driving unit 60. Inan embodiment of the present disclosure, the control unit 40 is alsoarranged on the base 10, so that the gear processing device 1 of thepresent disclosure can form an integrated design, but the presentdisclosure is not limited to this. For example, the control unit 40 canbe separated from the base 10 in structural, and be electricallyconnected to the driving unit 60 only by wires. The control unit 40 canbe a control chip, a processor or a computer host, etc., fortransmitting instructions to control the driving unit 60 to drive thebearing unit 20 or/and the grinding assembly 30 so as to drive thegrinding element 321 to perform the grinding operation on the gear to beprocessed.

In addition, in an embodiment of the present disclosure, the gearprocessing device 1 of the present disclosure further includes a powersupply unit 50, which is electrically connected to the driving unit 60,the bearing unit 20, the grinding assembly 30, and the control unit 40.The power supply unit 50 can be connected to an external power supply toprovide the power required by the aforementioned units.

In addition to using the driving unit 60 to drive the bearing portion 22and the grinding element 321 to move relative to each other to position,and to drive the grinding element 321 and the gear to be processed torotate respectively, during the grinding process, the gear processingdevice 1 of the present disclosure mainly uses the control unit 40 tocontrol the driving unit 60 to apply an additional motion to at leastone of the plurality of first corresponding axial directions(corresponding to the bearing unit 20) or/and at least one of theplurality of second corresponding axial directions (corresponding to thegrinding assembly 30), so that the bearing portion 22 or/and thegrinding element 321 will be driven by the driving unit 60, and thegrinding operation is performed in the state where the additional motionis executed or after the additional movement has been executed.

In an embodiment of the present disclosure, the additional motionapplied by the driving unit 60 to any corresponding axial direction maybe a one-time motion or a continuous motion. The one-time motion here isdefined relative to the continuous motion. The one-time motion isdefined as moving an object from a first position to a second position,so that the object produces a one-time spatial position change. Thecontinuous motion is defined as the repeated motion of an object betweendifferent positions, so that the object continuously changes its spatialposition.

Please refer to FIGS. 1 to 4 together, in which FIG. 3 is a schematicdiagram of the additional motion performed by the gear processing deviceof the present disclosure on the rotating axis corresponding to thebearing unit, and FIG. 4 is a schematic diagram of the change of thecontact area between the grinding element and the tooth surface of thegear before and after the additional motion shown in FIG. 3 isperformed. In an embodiment of the present disclosure, theaforementioned additional motion is a one-time axial offset motion,which is only applied to the rotation axis of the plurality of firstcorresponding axial directions of the bearing unit 20. As shown in FIGS.2 and 3, in this embodiment, the bearing unit 20 further includes amoving part 21. One end of the moving part 21 is connected to thebearing portion 22, and the moving part 21 can be driven by the drivingunit 60 to rotate relative to the base 10 based on the rotation axis A.Here, the rotation axis A is a horizontal axis through the rotation axisof the grinding unit 321 and the rotation axis of the gear G at the sametime. After the moving part 21 rotates based on the rotation axis A, themoving part 21 can drive the bearing portion 22 and the placed gear G torotate based on an axial direction R, thereby changing the installationangle of the gear G. In the standard motion, the installation angle isequivalent to the axis angle of the grinding unit 321 and the gear G. Inthe present disclosure, an additional installation angle can be addedthrough the foregoing operation to change the original relationshipbetween the grinding unit 321 and the gear G.

As shown in FIGS. 3 and 4, generally during the grinding process, thecenter O1 of the contact area of the grinding element 321 and the toothsurface of the gear G (shown by the dark-colored diagonal area in FIG.4) will remain on the plane P where the axis of the grinding element 321and the rotation axis A are located, and the additional installationangle γ_(a) of the gear G is defined as 0 at this time. However, asshown in FIGS. 3 and 4, by applying a one-time motion to the rotationaxis A, an additional installation angle γ_(a) of the gear G can beincreased. At this time, the gear G forms an axial rotational offset,and the position of the contact area of the grinding element 321 and thetooth surface of the gear G can be changed. By adjusting the additionalinstallation angle γ_(a) of the gear G by the one-time motion, thecontact area of the grinding element 321 and one side of the toothsurface of the gear G will shift downwards (as shown in thelight-colored diagonal area in FIG. 4, but the contact area of theelement 321 and the other side of the tooth surface of the gear G willshift upwards), so that the center O2 of the contact area is not on theplane P where the axis of the grinding element 321 and the rotation axisA applied the one-time motion are located. Accordingly, the tangentialdirection of the grinding element 321 during the grinding process is notparallel to the tooth groove direction of the gear G, thereby changingthe direction of the grinding texture produced by the grinding element321 on the tooth surface of the gear G.

Please refer to FIG. 1 and FIG. 5 together. FIG. 5 is a schematicdiagram of a comparison of the grinding results of the tooth surface ofthe gear of the control group A1 and the experimental group B1 of thegear processing device of the present disclosure. In the followingexperiment, the gear processing device 1 of the present disclosure isused to perform once grinding operation on the tooth surface of the gearof the same specification. The control group A1 was set under thecondition that no additional motion was applied to the aforementionedrotating axis A. The experimental group B1 was set under the conditionthat a one-time motion was applied to the rotation axis A to increasethe additional installation angle γ_(a) of the gear G by 1.5°. The imageof the grinding result along the axial direction and the tooth profiledirection of the gear after the grinding operation can be simulated andobtained. Wherein, the rotational speed of the worm grinding wheel is6000 rpm, the feed rate of the axial direction of the workpiece gear is500 mm/min, the helix angle is 25°, and the wheel radius of the wormgrinding wheel is 200 mm.

As shown in FIG. 5, after analyzing the experimental simulation results,it can be seen that the grinding texture of the control group A1 isroughly straight grinding texture, while the grinding texture of theexperimental group B1 is roughly oblique grinding texture. When thegrinding texture is oblique grinding texture, it can effectively reducethe single-frequency noise caused by gear meshing. Accordingly, theexperimental group B1 with one-time motion can produce better noisereduction effect than the control group A1.

In addition, when the additional installation angle γ_(a) is added tothe gear G, it will cause the geometric deviation of the tooth surfaceof the gear G. Therefore, it is necessary to generate motion modifiedparameters for the additional motions of other axial directions throughthe worm grinding wheel dressing and gear grinding process to correctthis deviation. The motion modified parameter here can be a function ofconstant, time or movement of other axis. Combining the aforementionedmotion modified parameters with the original motion equations of eachaxis in the gear processing device of the present disclosure, thegrinding control equation corresponding to each axis can be obtained,and then the grinding texture of the tooth surface of the gear can becalculated. The grinding control equation corresponding to each axis isas follow:

$\quad\left\{ \begin{matrix}{\psi_{A} = {\gamma_{wg} + \gamma_{a}}} \\{{F_{X\; 1}\left( \psi_{w} \right)} = {r_{d} + r_{w} + {f_{X\; 1}\left( \psi_{w} \right)}}} \\{{F_{Y\; 1}\left( \psi_{w} \right)} = {{{\pm p_{w}}\frac{\psi_{w}}{2\pi}} + {f_{Y\; 1}\left( \psi_{w} \right)}}} \\{{\psi_{A\; 1}\left( \psi_{w} \right)} = {\gamma_{dw} + {f_{A\; 1}\left( \psi_{w} \right)}}} \\{{F_{X}\left( F_{Z} \right)} = {r_{w} + r_{g} + {xm}_{n} + {f_{X}\left( F_{Z} \right)}}} \\{{F_{Y}\left( F_{Z} \right)} = {{\frac{b_{w}}{b_{g}}F_{Z}} + {f_{Y}\left( F_{Z} \right)}}} \\{{\psi_{C}\left( {\psi_{B},F_{Z}} \right)} = {{{\pm \psi_{B}}\frac{T_{w}}{T_{g}}\frac{b_{w}}{b_{g}}\frac{F_{Z}}{p_{w}}} + \frac{\tan\;\beta_{g}F_{Z}}{r_{g}}}}\end{matrix} \right.$

Where ƒ is the modified motion function, and γ_(a) is the additionalinstallation angle.

Reference is made to FIGS. 1 and 6 collectively, where FIG. 6 is aschematic diagram of the additional motion performed by the grindingunit of the gear processing device of the present disclosure. As shownin FIG. 6, in an embodiment of the present disclosure, the additionalmotion is a continuous and slight wave motion, and the wave motion isselected from at least one or a combination of the following groups: asine wave motion, a square wave motion, a triangle wave motion or asawtooth wave motion. Each wave motion has corresponding amplitude andfrequency, and the amplitude or frequency of the wave motion can beadjusted according to different requirements.

In an embodiment of the present disclosure, the control unit 40 cancontrol the driving unit 60 to apply the different wave motions to atleast two of the plurality of second corresponding axial directions ofthe grinding assembly during the grinding process. For example, assumingthat the plurality of second corresponding axial directions include theX axis and the Y axis, the control unit 40 can control the driving unit60 to apply a square wave motion to the X axis and apply a sine wavemotion to the Y axis. Furthermore, it is assumed that the plurality ofsecond corresponding axial directions include X axis, Y axis, and Zaxis. The control unit 40 can control the driving unit 60 to apply asquare wave motion to the X axis, apply a sine wave motion to the Yaxis, and apply a triangle wave motion to the Z axis, but the presentdisclosure is not limited thereto and may be changed according todifferent needs.

In an embodiment of the present disclosure, the control unit 40 cancontrol the driving unit 60 to apply the same wave motions withdifferent amplitudes or frequencies to at least two of the plurality ofsecond corresponding axial directions of the grinding unit during thegrinding process. For example, assuming that the plurality secondcorresponding axial directions include the X axis and the Y axis, thecontrol unit 40 can control the driving unit 60 to apply a sine wavemotion to both the X axis and the Y axis, but the amplitude of the sinewave motion applied to the X axis is 3.6 μm and the frequency of thesine wave motion applied to the X axis is 30 Hz, while the amplitude ofthe sine wave motion applied to the Y axis is 5.0 μm and the frequencyof the sine wave motion applied to the Y axis is 30 Hz. However, thepresent disclosure is not limited thereto and may be changed accordingto different needs.

In an embodiment of the present disclosure, the wave motion equationscorresponding to different wave motions applied to any axis is asfollows:

$\begin{matrix}{{\text{?}(t)} = {a_{1}{\sin\left( {b_{1}2\pi\;{ft}} \right)}}} & (1) \\{{\text{?}(t)} = {{\frac{4a_{2}}{\pi}\text{?}} - {\frac{1}{\left( {i + 1} \right)}{\sin\left\lbrack {\left( {i + 1} \right)b_{2}2{\pi{ft}}} \right\rbrack}}}} & (2) \\\left. \left. {{\text{?}(t)} = {{a_{3}\left\{ {\text{?}\frac{1}{\left( {i + 4} \right)^{2}}{\sin\left\lbrack {\left( {i + 4} \right)\text{?}2{\pi ft}} \right)}} \right\rbrack} + {\text{?}\frac{- 1}{\left( {j + 4} \right)^{2}}{\sin\left\lbrack {\left( {j + 4} \right)\text{?}2{\pi{ft}}} \right)}}}} \right\rbrack \right\} & (3) \\{{{{\text{?}(t)} = {{a_{4}\text{?}} - {\frac{2}{i\;\pi}{\sin\left( {{ib}_{4}2{\pi{ft}}} \right)}}}}\left( {{n_{2} = 20},{n_{3} = {n_{4} = 50}},{\omega = {2\pi\; f}}} \right){\text{?}\text{indicates text missing or illegible when filed}}}\mspace{275mu}} & (4)\end{matrix}$

In the above equations, the subscripts 1 to 4 of v, a, b, and nrepresent a sine wave, a square wave, a triangle wave and a sawtoothwave respectively. That is to say, the equation (1) represents theequation for applying the sine wave motion, equation (2) represents theequation for applying the square wave motion, equation (3) representsthe equation for applying the triangle wave motion, and equation (4)represents the equation for applying sawtooth wave motion. Wherein a andb respectively control the amplitude and the frequency of the waveform,ω is the rotation speed, t is the time, and f is the frequency. When thevalue of n is larger, the waveform is closer to the true shape.

By combining the above corresponding wave motion equation with theoriginal motion equation of each axis in the gear processing device ofthe present disclosure, the grinding control equations corresponding toeach axis can be obtained, and then roughness of the tooth surface andthe shape of the grinding texture of the gear can be calculated.

Please refer to FIGS. 1 and 7 together. FIG. 7 is a schematic diagram ofa comparison of the grinding results of the tooth surface of the gear ofthe control group A2 and the experimental group B2˜E2 of the gearprocessing device of the present disclosure. In the followingexperiment, the gear processing device 1 of the present disclosure isused to perform once grinding operation on the tooth surface of the gearof the same specification. The control group A2 was set under theconditions that no wave motion was applied to the X axis, the Y axis andthe Z axis. The experimental group B2 was set under the conditions thatthe sine wave motion was applied to the X axis, the Y axis and the Zaxis. The experimental group C2 was set under the conditions that thesquare wave motion was applied to the X axis, the Y axis and the Z axis.The experimental group D2 was set under the conditions that thetriangular wave motion was applied to the X axis, the Y axis and the Zaxis. The experimental group E2 was set under the conditions that thesawtooth wave motion was applied to the X axis, the Y axis and the Zaxis. The image of the grinding result along the axial direction and thetooth profile direction of the gear after the grinding operation, themaximum grinding texture depth of the tooth surface and the value of thetooth surface roughness can be simulated and obtained. Wherein, thefrequencies of all wave motions to be applied are 30 Hz, the amplitudesof all wave motions applied to the X axis are 3.6 μm, and the amplitudesof all wave motions applied to the Y axis are 5.0 μm, and the amplitudesof all wave motions applied to the Z axis are 4.0 μm. The feed rate ofthe axial direction of the worm grinding wheel is 20 mm/s, the helixangle is 0°, the wheel radius of the worm grinding wheel is 200 mm, andthe abrasive particle size of the worm grinding wheel is 470 μm.

As shown in FIG. 7, after analyzing the experimental simulation results,it can be seen that the grinding texture of the control group A2 isroughly straight, while the grinding texture of the experimental groupsB2 and D2 is roughly staggered, while the grinding texture of theexperimental groups C2 and E2 are roughly straight grinding texturesimilar to those of the control group A2. When the grinding texture isoblique grinding texture, it can effectively reduce the single-frequencynoise caused by gear meshing. Accordingly, the experimental groups B2and D2 that applied the sine wave motion can produce better noisereduction effects than the control group A2. However, the experimentalgroups C2 and E2 that applied the square wave motion did not achievemuch improvement in the shape of the grinding texture of the toothsurface.

Then, in terms of the maximum grinding texture depth h_(max), themaximum grinding texture depth of the control group A2 is approximately1.60 μm, the maximum grinding texture depth of the experimental group B2is approximately 1.44 μm, the maximum grinding texture depth of theexperimental group C2 is approximately 1.62 μm, the maximum grindingtexture depth of the experimental group D2 is about 1.34 μm, and themaximum grinding texture depth of the experimental group E2 is about1.57 μm. Compared with the control group A2, the maximum grindingtexture depth of the experimental groups B2 and D2 decreased by about16%, while the improvement for the grinding texture depth of theexperimental groups C2 and E2 had been limited.

In terms of tooth surface roughness R_(a), the tooth surface roughnessof the control group A2 is about 0.422 μm, the tooth surface roughnessof the experimental group B2 is about 0.473 μm, the tooth surfaceroughness of the experimental group C2 is about 0.246 μm, the toothsurface roughness of the experimental group D2 is about 0.430 μm, andthe tooth surface roughness of the experimental group E2 is about 0.387μm. Compared with the control group A2, the improvement effect for thevalue of the tooth surface roughness of the experimental group C2 issignificantly better than the experimental group B2, D2 and E2.

Reference is next made to FIG. 8, which is a flowchart of the gearprocessing method of the present disclosure. As shown in FIG. 8, thepresent disclosure further includes a gear processing method, which canbe applied to the gear processing device of the present disclosure orother devices with similar functional characteristics. The gearprocessing method of the present disclosure includes the followingsteps:

Step S1: a gear processing device is provided. The gear processingdevice includes a driving unit, a bearing unit that carries the gear,and a grinding assembly, and the grinding assembly includes a grindingelement.

Step S2: Utilize the driving unit to drive the bearing unit to perform amotion of a plurality of first corresponding axial directions relativeto the base and drive the grinding assembly to perform a motion of aplurality of second corresponding axial directions relative to thebearing unit, so as to make the grinding element contacts the toothsurface of the gear; wherein the driving unit applies an additionalmotion to at least one of the plurality of first corresponding axialdirections or/and at least one of the plurality of second correspondingaxial directions during the grinding process, so as to change thedirection of the grinding texture produced by the grinding element onthe tooth surface of the gear.

In summary, the gear processing device and method of the presentdisclosure can change the shape, angle and depth of the grinding textureof the tooth surface of the gear by applying a small amount ofadditional motion to at least one of the plurality of axial directionswhen the bearing unit or/and the grinding assembly perform the motionsof the plural axial directions to form different tooth surfaceroughness, thereby reducing the noise caused by vibration when the gearhas meshed and improving the quality and efficiency of the processinggear.

In the above, the present disclosure based on the multi-directionalmulti-joint turning piece and display device have been described, butthe present embodiment can be modified in various ways other than theabove-mentioned embodiment as long as it does not deviate from its gist.The various embodiments and modifications described above can beimplemented in an appropriate combination.

What is claimed is:
 1. A gear processing device for performing a surfaceprocessing on a tooth surface of a gear, comprising: a base; a drivingunit arranged on the base; a bearing unit arranged on the base, whereinthe bearing unit is used for bearing the gear, and the bearing unit isdriven by the driving unit to perform a motion with a plurality of firstcorresponding axial directions relative to the base; a grinding assemblyarranged on the base, wherein the grinding assembly includes a grindingelement, and the grinding assembly is driven by the driving unit toperform a motion with a plurality of second corresponding axialdirections relative to the bearing unit, so that the grinding elementcontacts the tooth surface of the gear; and a control unit electricallyconnected to the driving unit, wherein the control unit is used tocontrol the driving unit to apply an additional motion to at least oneof the plurality of first corresponding axial directions, or/and atleast one of the plurality of second corresponding axial directionsduring a grinding process to change direction of the grinding textureproduced by the grinding element on the tooth surface of the gear. 2.The gear processing device of claim 1, wherein the additional motion isa one-time motion or a continuous motion.
 3. The gear processing deviceof claim 2, wherein an additional installation angle of the gear isadjusted by the one-time motion, so that a center of a contact area ofthe grinding element and the tooth surface of the gear is not on a planewhere an axis of the grinding element and a rotation axis applied theone-time motion are located.
 4. The gear processing device of claim 2,wherein the continuous motion is a wave motion.
 5. The gear processingdevice of claim 4, wherein the wave motion is selected from at least oneor a combination of the following groups: a sine wave motion, a squarewave motion, a triangle wave motion, or a sawtooth wave motion.
 6. Thegear processing device of claim 5, wherein the control unit controls thedriving unit to apply the different wave motions to at least two of theplurality of second corresponding axial directions during the grindingprocess.
 7. The gear processing device of claim 5, wherein the controlunit controls the driving unit to apply the same wave motions withdifferent amplitudes or frequencies to at least two of the plurality ofsecond corresponding axial directions during the grinding process. 8.The gear processing device of claim 1, wherein the grinding element is agrinding wheel.
 9. The gear processing device of claim 1, wherein theplurality of first corresponding axial directions or the plurality ofsecond corresponding axial directions are at least two selected from thefollowing groups: three moving axes and three rotating axescorresponding to six degrees of freedom.
 10. A gear processing methodfor performing a surface processing on a tooth surface of a gear, thegear processing method comprising: providing a gear processing device,wherein the gear processing device includes a driving unit, a bearingunit that bears the gear, and a grinding assembly includes a grindingelement; and applying the driving unit to drive the bearing unit toperform a motion of a plurality of first corresponding axial directionsrelative to the base or/and to drive the grinding assembly to perform amotion of a plurality of second corresponding axial movements relativeto the bearing unit, so as to make the grinding element to contact thetooth surface of the gear; wherein the driving unit applies anadditional motion to at least one of the plurality of firstcorresponding axial directions or/and at least one of the plurality ofsecond corresponding axial directions during a grinding process, so asto change the direction of the grinding texture produced by the grindingelement on the tooth surface of the gear.
 11. The gear processing methodof claim 10, wherein the additional motion is a one-time motion or acontinuous motion.
 12. The gear processing method of claim 11, whereinan additional installation angle of the gear is adjusted by the one-timemotion, so that a center of a contact area of the grinding element andthe tooth surface of the gear is not on a plane where an axis of thegrinding element and a rotation axis applied the one-time motion arelocated.
 13. The gear processing method of claim 11, wherein thecontinuous motion is a wave motion.
 14. The gear processing method ofclaim 13, wherein the wave motion is selected from at least one or acombination of the following groups: a sine wave motion, a square wavemotion, a triangle wave motion, or a sawtooth wave motion.
 15. The gearprocessing method of claim 14, wherein the driving unit applies thedifferent wave motions to at least two of the plurality of secondcorresponding axial directions during the grinding process.
 16. The gearprocessing method of claim 14, wherein the driving unit applies the samewave motions with different amplitudes or frequencies to at least two ofthe plurality of second corresponding axial directions respectivelyduring the grinding process.